1. Field of the Invention
The present invention relates to a battery pack assembly for providing electrical power.
2. Description of the Prior Art
It is well known to combine a number of battery packs, each including a number of individual cells, for providing electrical power. Heat is generated as electrical current flows into and out of the cells, which heat can have a significant negative impact on the performance and lifetime of the cells and of the battery pack assembly as a whole, if the heat is not effectively managed. Limiting and maintaining the temperature across the various cells in the multiple battery packs can be important in maximizing the performance and lifetime of the entire battery pack assembly.
To maintain the battery packs and the cells at a desired temperature, a cooling system is often provided within the battery pack assembly. Conventionally, these cooling systems pass air over and around the battery packs and the cells via an inlet manifold and an outlet manifold. In this type of system, the cooling air absorbs heat as it passes over the cells and loses its capacity to absorb heat as it passes over the cells to create temperatures cooler near the inlet manifold than the warmer temperatures near the outlet manifold.
The U.S. Pat. No. 6,569,556 to Zhou et al., discloses such a cooling system including an inlet manifold and an outlet manifold that direct an air flow through the cells.
Although the prior art discloses systems that cool cells and battery packs within a battery pack assembly by passing cooling air through the assembly, significant temperature differences occur from battery pack to battery pack and from cell to cell due to the non-uniform nature of the source of the cooling air. These temperature differences are detrimental to the performance and lifetime of the battery pack assembly.